[PATCH] net/iavf: fix old GCC compilation warnings

[Zhichao Zeng]

The code uses the Wimplicit-fallthrough compile option to ignore
falls through warnings in switch case, but this option was introduced
by GCC 7 and old GCC do not recognize the option.

Add judgment to avoid warnings about unrecognized options in old GCC.

Fixes: 95a1b0b23140 ("net/iavf: support Rx timestamp offload on SSE")
Fixes: 4f58266da4d3 ("net/iavf: support Rx timestamp offload on AVX2")
Fixes: d65eadb9e178 ("net/iavf: support Rx timestamp offload on AVX512")
Signed-off-by: Zhichao Zeng <zhichaox.z...@intel.com>
---
 drivers/net/iavf/iavf_rxtx_vec_avx2.c   | 10 +++++++---
 drivers/net/iavf/iavf_rxtx_vec_avx512.c | 10 +++++++---
 drivers/net/iavf/iavf_rxtx_vec_sse.c    | 10 +++++++---
 3 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/net/iavf/iavf_rxtx_vec_avx2.c 
b/drivers/net/iavf/iavf_rxtx_vec_avx2.c
index 86290c4bbb..25094d5958 100644
--- a/drivers/net/iavf/iavf_rxtx_vec_avx2.c
+++ b/drivers/net/iavf/iavf_rxtx_vec_avx2.c
@@ -1397,8 +1397,10 @@ _iavf_recv_raw_pkts_vec_avx2_flex_rxd(struct 
iavf_rx_queue *rxq,
                                        (_mm256_castsi256_si128(status0_7)));
                received += burst;
 #ifndef RTE_LIBRTE_IAVF_16BYTE_RX_DESC
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#if __GNUC__ >= 7
+       #pragma GCC diagnostic push
+       #pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#endif
                if (rxq->offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP) {
                        inflection_point = (inflection_point <= burst) ? 
inflection_point : 0;
                        switch (inflection_point) {
@@ -1436,7 +1438,9 @@ _iavf_recv_raw_pkts_vec_avx2_flex_rxd(struct 
iavf_rx_queue *rxq,
 
                        rxq->hw_time_update = rte_get_timer_cycles() / 
(rte_get_timer_hz() / 1000);
                }
-#pragma GCC diagnostic pop
+#if __GNUC__ >= 7
+       #pragma GCC diagnostic pop
+#endif
 #endif
                if (burst != IAVF_DESCS_PER_LOOP_AVX)
                        break;
diff --git a/drivers/net/iavf/iavf_rxtx_vec_avx512.c 
b/drivers/net/iavf/iavf_rxtx_vec_avx512.c
index f9961e53b8..b74a6443b3 100644
--- a/drivers/net/iavf/iavf_rxtx_vec_avx512.c
+++ b/drivers/net/iavf/iavf_rxtx_vec_avx512.c
@@ -1551,8 +1551,10 @@ _iavf_recv_raw_pkts_vec_avx512_flex_rxd(struct 
iavf_rx_queue *rxq,
                received += burst;
 #ifndef RTE_LIBRTE_IAVF_16BYTE_RX_DESC
 #ifdef IAVF_RX_TS_OFFLOAD
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#if __GNUC__ >= 7
+       #pragma GCC diagnostic push
+       #pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#endif
                if (rxq->offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP) {
                        inflection_point = (inflection_point <= burst) ? 
inflection_point : 0;
                        switch (inflection_point) {
@@ -1590,7 +1592,9 @@ _iavf_recv_raw_pkts_vec_avx512_flex_rxd(struct 
iavf_rx_queue *rxq,
 
                        rxq->hw_time_update = rte_get_timer_cycles() / 
(rte_get_timer_hz() / 1000);
                }
-#pragma GCC diagnostic pop
+#if __GNUC__ >= 7
+       #pragma GCC diagnostic pop
+#endif
 #endif
 #endif
                if (burst != IAVF_DESCS_PER_LOOP_AVX)
diff --git a/drivers/net/iavf/iavf_rxtx_vec_sse.c 
b/drivers/net/iavf/iavf_rxtx_vec_sse.c
index b754122c51..ff364d4fe5 100644
--- a/drivers/net/iavf/iavf_rxtx_vec_sse.c
+++ b/drivers/net/iavf/iavf_rxtx_vec_sse.c
@@ -1126,8 +1126,10 @@ _recv_raw_pkts_vec_flex_rxd(struct iavf_rx_queue *rxq,
                nb_pkts_recd += var;
 
 #ifndef RTE_LIBRTE_IAVF_16BYTE_RX_DESC
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#if __GNUC__ >= 7
+       #pragma GCC diagnostic push
+       #pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
+#endif
                if (rxq->offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP) {
                        inflection_point = (inflection_point <= var) ? 
inflection_point : 0;
                        switch (inflection_point) {
@@ -1153,7 +1155,9 @@ _recv_raw_pkts_vec_flex_rxd(struct iavf_rx_queue *rxq,
 
                        rxq->hw_time_update = rte_get_timer_cycles() / 
(rte_get_timer_hz() / 1000);
                }
-#pragma GCC diagnostic pop
+#if __GNUC__ >= 7
+       #pragma GCC diagnostic pop
+#endif
 #endif
 
                if (likely(var != IAVF_VPMD_DESCS_PER_LOOP))
-- 
2.34.1